The Mermaid Theory Revisited
by manda600
Summary: Six years into the future, Robin fears Barney's "Mermaid Theory" will spell the end of their marriage.
1. Chapter 1

_2017_

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><p>It was hard for Barney to believe, but he and Robin had been married for four years now. It hadn't been a smooth or easy road to the altar, but he'd do it all again in a heartbeat.<p>

Back in 2012, seeing his future there before him in her sparkling brown eyes – a nauseatingly romantic analogy he'd allow simply because of the stellar Robin Sparkles callback – Barney had decided to stop being scared and be awesome instead. And he'd never looked back.

Of course, reconnecting with his father had certainly helped get him to that point. At first he'd hated his dad's conventional ordinariness, the horrible cliché of a "family man". Then he'd resented it, envied it for himself as a child. Once he'd made peace with their past, however, he'd begun to envy it _now_, for himself as a man. And once he'd started to really contemplate the possibility of marriage and monogamy, of spending his life with just one woman, only one woman came to mind. He tried others, but it was never quite the same. There was simply no comparison. He figured out the hard way it was Robin. It had always been Robin, it always would be Robin. He'd never stopped loving her, certainly never stopped wanting her, and he finally discovered – thank God – she felt the same way.

And so Barney Stinson and Robin Scherbatsky had made the greatest leap of all, into married life, and surprisingly it hadn't sucked the awesome out of them at all. Defying their friends' predictions, they could be in love, they could be committed, they could even be _legally married_, and still be Barnman and Robin, their rockingly awesome selves – without antiquing or farmer's markets or any of that other lame couply stuff that so wasn't them. Still, marriage was one thing, but they weren't yet ready to go so far as actually having a kid, the way everyone else in their lives had.

But fate had other plans for them.

Well, actually, it was a broken condom that couldn't quite stand their fervor while experimenting with – man was he glad he bookmarked that website all those years ago. Robin had thought it would be alright, that it was the wrong time of the month. Apparently she didn't know her body quite as well as she thought she did

Then again, it might not have been the broken condom at all. It could've been later that week…..

The second time around, he and Robin had managed to work out the kinks in their previous relationship. They'd matured. They'd learned to compromise, to express their feelings. They no longer had killer plate-throwing fights. Nevertheless, similar personalities will clash at times. But now they had softer, gentler "disagreements" that – because they were Barnman and Robin – they channeled into heated exhilarating one-upmanship that always ended in the same mutually enjoyable way, that particular time in the back alley behind MacLaren's.

As they had such a penchant for public, outdoor, anytime-anywhere-the-mood-strikes sex, they found that, while there was an endless supply at home, they were out of on-the-go condoms. But both were unwilling and – let's be honest – _unable_ to stop.

Always hyper-vigilant – because obviously the Barnacle has super sperm – Barney had shockingly never had unprotected sex in his life. But waiting was just not an option; come on, clothes were undone and they were already halfway there. The "wrong time of the month" philosophy provided a convenient excuse to gloriously bring it the rest of the way home. What up.

The end result was a big fat + on all four of the tests Robin had purchased.

While children had never been in their game plan – it was an issue they expressly put off time and time again – once they'd actually made one, it was a different story. It took a little time to get used to the idea but, after all, this was _their_ baby; it had to be awesome.

Of course a new story needed to be invented for the child's conception, as either 'a quickie in an alley outside a bar' or 'whilst working our through a manual of Canadian sexual positions' wasn't exactly an appropriate beginning. It was an awful legendary one though.


	2. Chapter 2

Robin had made peace with kids once Marshall and Lily starting having theirs. Shockingly, she discovered the little guys weren't so bad. She even decided she'd definitely like one someday. She just wasn't sure if she was quite ready yet to grow one herself. But babies really weren't so scary, not once you knew what you were doing with them. Thanks to Lily's sink-or-swim method, she now did.

Ted and his wife started trying for a baby immediately too, although he was crazy overprotective with his kids. It was at the hands of Lily where Robin learned all maternal skills, as her friend often touted, "You just never know". Lily seemed to be anticipating the broken condom from the very beginning of their marriage ("They're only effective 97 out of 100 times," she'd said. "With you two, I assumed those odds would get you within the first two months.")

After the initial shock, Barney had seemed more freaked out by it than Robin, who – in what she'd since deemed the sock incident – had started entertaining the idea of maybe, perhaps, someday way down the line wanting a child as far back as when Lily and Marshall had first felt stirrings. It was only natural that it would take the founder of Not A Father's Day a little longer to come around.

But come around he did. Robin's pregnancy had been unexpected, unplanned, but not necessarily unwanted. Like his thoughts on marriage, Barney's thoughts on children had undergone a shift in recent years. As long ago as when his nephew first came along he'd secretly thought little kids weren't so bad – at least in small dosages. Then, in more recent years, when Marshmallow and Lilypad started procreating, then the Mosbys after that, and he became Uncle Barney five times over, he had to admit he kind of liked it. And if _those_ kids had potential, imagine what his and Robin's kid would be like.

By genetics alone, their child would be far from ordinary. Rearing would take care of the rest. The one advantage of a crappy childhood was to know what _not_ to do; that was something both he and Robin had learned in spades. Still, there'd be no pansy-ass upbringing like Ted's kids were getting. If it was a boy, first thing out of the womb he would be measured for a tailored suit; being an infant was no excuse not to suit up when the occasion called for it. And if it was a girl, as Lily predicted – because what more poetic justice could there be in the world than for Barney Stinson to have a daughter – well he'd just use his playbook in a sort of reverse advantage. He'd begin schooling her in the ways of boys by the time she was five, maybe six. With her father's experience and knowledgebase combined with her mother's cleverness and natural resistance to bullshitting men, no guy would get anything past their daughter.

Robin always smiled and laughed when he said things like that. Her husband had forever been such a study in contradictions. For a man who'd spent years being so vocally anti-child, she'd never seen a better, more caring uncle. Barney seemed to have a natural way with them – women _and_ babies.

She knew he'd warmed to the idea of their child when he gave up smoking for good this time; he'd had his very last cigarette back in March, a week after she'd found out she was pregnant. Then their nightly sleeping pattern began to gradually change just a bit. Spooning, post-sex, Barney would always position his hand at her hip, or thigh, or even around her breast, but now more often than not it rested protectively on her stomach.

While they'd both confided in one other their private doubts on their ability to be a good parent, together they'd determined to handle parenthood as they did all other situations, with great aplomb. Everything had calmed down and settled in. It seemed as if they were on their way to being a normal – _awesome_ – happy family…until Robin's body began changing and the weight started to come on. That's when it all went north for her.

Yesterday, the button on her pants had popped – only after she couldn't get the first pair zipped. And now she learned she was supposed to attend the broadcasting awards banquet the month after next. She had to go; she was nominated. But if she couldn't fit in her clothes now, she'd look like an absolute cow by then. How could she be expected to look decent in formalwear when she was giving Jabba the Hutt a run for his money? She smiled, thinking Barney would appreciate the Star Wars reference, but then it dawned on her: she knew _he_ would also agree. That's when she really started feeling nauseous…


	3. Chapter 3

It was pitch black in the apartment when Barney got home from the office, blinds shut tight not even allowing the city lights inside.

"Robin?"

Negations had been tense at work and he was late getting home, but it was barely eight o'clock, much too early for bed. Maybe she went out? But when he called earlier to say he'd be late, she'd told him she was just going home.

As his eyes adjusted to the darkness, he could just make out her figure in the far chair. He flipped on the lights and his suspicions were confirmed; she was upset. She'd been crying – or at least trying not to.

"What's the matter?" he asked softly. "Bad day at work?"

"I wish that was all."

"Okay. Not work. Then what is it?"

"You know."

"No."

"Yes_,_ _you do_," she insisted with an emphasis.

He gave her a funny look. "Um, no. I don't. That's kinda why I'm asking." She usually wasn't one for such womanly arts as coyness and evasion. She said what she wanted and went after it with directness. He'd always admired that about her.

Robin shook her head, standing up. "I know you're lying to me, Barney. I know. And I get it. I do. I don't even blame you. But let's just face this head-on. We're doomed."

" 'We'? As in….you and me?" he asked in confusion, pointing between them.

"Our marriage."

He attempted to keep the smile off his face at this melodrama that was so not her, but he couldn't help it, especially considering that their relationship had never been better. "And why are we 'doomed' exactly?"

"Because you're Barney Stinson, and I know – _everybody_ knows – that you need sex regularly or you get all twitchy."

He ran his eyes over her, slowing at the good parts. "So do you, Scherbatsky," he said suggestively.

In a turn of good fortune, pregnancy had increased her already considerable libido. The week before last she'd met him at the door stark naked. They had sex on the couch, in the shower, and – when he, Barney Stinson of all people, actually tried to get her to stop long enough for her to eat a proper meal – once on the kitchen table.

All day long at work he'd frankly been hoping for a repeat. In great detail, he'd been _imagining_ a repeat. It was all he could do to keep half an ear on the North Koreans while his mind was busy picturing his wife nude, spread eagle on their bed – a position he'd planned to get her into within ten minutes of walking through that door….

"Yeah, you're right; I love having sex with you. But look at me now," she said, in an increasingly upset tone, as she indicated her body. "I'm huge."

And the possibility of having her naked in ten minutes was looking more and more unlikely…..

"Robin – "

"I'm just – I'm not used to _not_ being hot," she cut him off. "I don't like it…..And I know it's only a matter of time – " She turned away from him then, refusing to meet his eyes. "It's only a matter of time before you can't stand to touch me anymore, and you'll start getting it somewhere else."

"Robin," he said, suddenly dead serious. He took hold of her shoulders, turning her back to face him. "You know I love you. And I have never, nor will I ever, cheat on you. Never. Not once. Not even way back before we had "the talk". Not then, not now, not ever. Hey," he said, holding her gaze, making sure she held his. "I mean it."

She nodded, acknowledging her belief in his words. "I know you do," she said. Her hand covered his at her shoulder, her forefinger rubbing softly over his wedding ring. "You mean it _now_. But you have your theory, your Mermaid Theory. You won't be able to help it. I'm just a….a manatee to you now…" Her voice wobbled and he could see her visibly trying to collect herself but failing miserably. "And you'll find a mermaid, or she'll find you, and you won't be able to resist." Here she broke off, full out crying.

Her tears streamed uncontrollably down her face, and Barney's heart pricked at the sight.

"Aww, come here," he said gently, gathering her into his arms, although he wasn't quite able to keep the laughter from his voice because this topic was ridiculous. Yeah, she's showing, but she was nowhere near 'huge'. What little weight there was had all settled in a baby bump right in her belly – and her boobs, God bless 'em. Plus, it's _Robin_. She's never had a shortage of men falling at her feet – him most of all. "That's what this is about? The Mermaid Theory? But you forget. There's an addendum to that rule. An exception, if you will."

She pulled back to look at him, shaking her head impatiently as if she already knew the answer. "Breastfeeding. But, Barney, that won't come for another five months. You'll never last that long."

"No, _another_ addendum." When he was certain he had her full attention, he announced with characteristic theatrics, "The DNA Exemption."

Robin sniffed. "What's that?" she asked, looking up at him in confusion mingled with an adorable light of hope that made him gather her closer against him.

"The DNA Exemption clearly states that the Manatee Clause is null and void if the child the woman's carrying is yours."

"What?" Robin said skeptically, certain he was making this up off-the-cuff. She pulled out of his arms, crossing the room for a Kleenex.

Barney watched her intently as she walked to the counter, eyes raking over her curves. "I never believed it myself until now, but…" He paused, slowly looking her up and down. "There's just something about seeing you this way…..knowing there's a little Stinson in there….knowing _I_ put it in there," he said amorously. "Knowing _how_ I put it in there – in great detail." Now at her side, he murmured, "I've the sexual memory of an elephant; I never forget a thing. Right down to the last moan and thrust," he added lasciviously, clearly picturing just that.

"Barney," she said with a hint of amusement despite herself, not chastising his lechery per se, just slightly annoyed that he'd gotten off topic.

"The point is, Robin, that you _are_ hot," he told her, stroking a stray hair behind her ear, his hand lingering at her neck. "You're always gonna be hot. I wanted you before, and I still want you now."

It was hard for him to believe she doubted it. He loved her body, had spent most of his day doing all sorts of dirty things to said body in his mind. Finally having her right there before him, it was all he could do to focus on their conversation. And the fact that she wore her clothes like a second skin – since she refused to buy a bigger, maternity size – did nothing to help his 'growing' problem.

But Robin was still skeptical. Crumpling her Kleenex and discarding it on the counter, she reached for her glass of water. Her blouse pulled tight across her swollen breasts, straining the overworked buttons and showing an outline of nipple through the silk.

"I _really_ want you right now," Barney said, rocking on his feet, his voice a lustful growl. He knew that nipple intimately and was more than ready to greet the old friend.

She finished her drink, still obviously not believing him. "Yeah right," she scoffed. "Because I'm just so sexy."

"Robin, are you kidding me? All I wanted all day long was to get home and just….completely go to town on you."

She shook her head, huffing out an unamused laugh. Turning away, she walked over to the window and nudged aside the blinds to stare blankly out. "Look, you don't have to lie to make me feel better, Barney. It's alright. I told you, I get it."

This time he was the one to shake his head. "No, I don't think you do."

He came up behind her, running his hand over her belly in a quick little caress. Then he took hold of her hips, pressing her back against his growing erection. For a moment, the only sound in the room was the knock of the blinds swinging closed again. "Does this feel like a lie?" he murmured, sinking his teeth into her neck.

Robin was quiet a long moment, letting his lips, teeth, and tongue work their magic over her neck. "No," she finally allowed, and it sounded to him like a bit of her confidence was returning. Actually, it sounded like her voice was sort of breathy, the way it gets when….

She reached back behind her, putting her hand to the nape of his neck and guiding his mouth to just the right spot. Her other hand slipped around his waist and beneath his suit coat to play at his belt. "Mmm," she sighed – more like moaned, really – as he sucked at her skin. It ought to be a crime what he could do to her – and they hadn't even gotten to the good stuff. Pregnancy had only heighted the sensation. Lily said it was something about the increased blood flow. Robin didn't know what it was. She only knew she wanted more of it. She pressed further into him. "_That_ doesn't feel like a lie." Grinding her bottom against him, she smiled at his answering groan. "Nope, not a lie at all."

"You're beautiful. You're incredible. You're _awesome_, Robin. How could you doubt that for a second?" Barney asked, his voice dropping low and his hands tightening at her hips as she continued her little gyrations. "I'm always gonna want you." He moved a hand up to squeeze her breast. "I'm always gonna want _these_. I mean, have you even looked in the mirror lately? Pa-cow!" he exclaimed, his hand rubbing over her breasts in a gesture worthy of any Price Is Right model. "These alone are going to keep me glued to your side."

Then his fingers were busying at her blouse, finally putting those suffering buttons out of their misery. In an instant his hand was inside, covering the lace of one overworked cup. "I can guarantee I'll be steadily hitting this all over the next five months – all the way until the contractions start. Creative-pregnancy-sex high five!"

Robin looked over her shoulder at Barney, her eyes a mixture of affection and heat. She shook her head and laughed, smiling that little smile that came right before…. "You're an idiot," she said, taking his hand – still frozen in midair – and placing it back on her body.

And by the time the night was over, he'd made her completely forgot there ever was a Mermaid Theory – along with everything else in the world outside the circumference of their bedroom.

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><p>Author's Note: I tried to slip in little call-backs to past episodes, obviously <em>The Mermaid Theory<em> (the source of Barney's view of pregnant women as manatees, up until the time they begin breastfeeding), but there were also little asides to _The Last Cigarette Ever_ (which gave the date of Barney's last cigarette), _Not A Father's_ _Day_ (both with Barney's avowal not to have kids, then maybe perhaps a slight mix of feelings with his own sock karaoke breakdown; and earlier with Robin's initial 'sock incident'), _Happily Ever After_ (when Robin uses the phrase things "went north" instead of "south"), _Robin 101_ (which introduced the 'You're an idiot' code phrase), and _Architect of Destruction_ (which established that Robin and Lily discuss their sex lives in explicit detail).


End file.
